U.S. patent application number 13/930562 was filed with the patent office on 2014-01-02 for piston engine.
The applicant listed for this patent is Northern Alberta Institute of Technology. Invention is credited to Peter Ross Taylor.
Application Number | 20140000550 13/930562 |
Document ID | / |
Family ID | 49776831 |
Filed Date | 2014-01-02 |
United States Patent
Application |
20140000550 |
Kind Code |
A1 |
Taylor; Peter Ross |
January 2, 2014 |
PISTON ENGINE
Abstract
A piston system comprises a first arm and a second arm, each
mounted respectively on a first shaft and a second shaft, and being
mounted for rotational oscillation about a central axis. Both arms
terminate radially outward from the central axis, and are coupled
to piston arrangements. The piston arrangements include pistons.
Each set of pistons is mounted for movement within respective
stationary chambers. Each stationary chamber may be defined, at
least in part, by a piston coupled to the first arm and a piston
coupled to the second arm. The stationary chambers are arranged
about the central axis. The first and the second shaft are
connected to an energy transfer mechanism. An energy transfer
mechanism includes coupled non-circular gears arranged to convert
oscillatory rotational motion to unidirectional rotational
motion.
Inventors: |
Taylor; Peter Ross;
(Edmonton, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Northern Alberta Institute of Technology |
Edmonton |
|
CA |
|
|
Family ID: |
49776831 |
Appl. No.: |
13/930562 |
Filed: |
June 28, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61666767 |
Jun 29, 2012 |
|
|
|
Current U.S.
Class: |
123/197.1 ;
74/25 |
Current CPC
Class: |
Y10T 74/18056 20150115;
F16H 2035/003 20130101; F02B 75/265 20130101; F01C 17/02 20130101;
Y02T 10/17 20130101; F01C 9/002 20130101; F16H 37/122 20130101;
Y02T 10/12 20130101 |
Class at
Publication: |
123/197.1 ;
74/25 |
International
Class: |
F16H 37/12 20060101
F16H037/12 |
Claims
1. A piston system, comprising: a first arm mounted on a first
shaft for rotation about a central axis; a second arm mounted on a
second shaft for rotation about the central axis; each of the first
arm and the second arm terminating radially outward from the
central axis in respective piston arrangements, each of the piston
arrangements including pistons mounted for movement within
respective stationary chambers, each stationary chamber being
defined at least in part by a piston of the first arm and a piston
of the second arm; each of the first shaft and the second shaft
being connected to an energy transfer mechanism; and the energy
transfer mechanism including coupled non-circular gears arranged to
convert oscillatory rotational motion to unidirectional rotational
motion.
2. The piston system of claim 1 in which the pistons are mounted
for circumferential movement and each stationary chamber extends
circumferentially about the central axis.
3. The piston system of claim 1 in which each of the first arm and
the second arm terminate radially outward from the central axis in
partial gear pinion sections coupled to the respective piston
arrangements, and each of the stationary chambers being
right-cylindrical stationary chambers.
4. The piston system of claim 3 in which the partial gear pinion
sections are coupled to idler gears and the idler gears are further
coupled to the respective piston arrangements, each stationary
chamber being defined at least in part by a piston of the first arm
and a piston of the second arm arranged so as to be directly
opposed to each other.
5. The piston systems of claim 1 in which each stationary chamber
is further defined by an engine block forming one half of each
stationary chamber and a head forming the other half of each
stationary chamber.
6. The piston system of claim 5 further comprising an intake port
and an exhaust port for each stationary chamber.
7. The piston system of claim 6, in which the intake port and the
exhaust port for each respective stationary chamber are located on
a surface of each respective stationary chamber not defined by a
piston.
8. The piston system of claim 7, in which the intake port and the
exhaust port for each respective stationary chamber are located on
the engine block.
9. The piston system of claim 8, in which both the intake port and
the exhaust port of each stationary chamber are equidistant from
the piston of the first arm and the piston of the second arm
defining at least in part each respective stationary chamber.
10. The piston system of claim 9, in which the intake port of each
respective stationary chamber has a greater surface area than the
exhaust port of each respective stationary chamber.
11. The piston system of claim 10, further comprising a respective
intake valve associated with each intake port and a respective
exhaust valve associated with each exhaust port.
12. The piston system of claim 11 in which each respective intake
valve and each respective exhaust valve comprises a poppet
valve.
13. The piston system of claim 12 in which opening and closing of
the intake valves and exhaust valves is controlled by a rotating
cam plate.
14. The piston system of claim 1 further comprising a respective
ignition mechanism for each stationary chamber.
15. The piston system of claim 1 in which the energy transfer
mechanism comprises: an energy transfer shaft; a first central
bilobe gear mounted for rotation about the central axis on the
first shaft; a second central bilobe gear mounted for rotation
about the central axis on the second shaft; and a gear stack
comprising a first planetary bilobe gear meshed with the first
central bilobe gear and a second planetary bilobe gear meshed with
the second central bilobe gear; and the first planetary bilobe gear
and the second planetary bilobe gear being connected to the energy
transfer shaft to rotate with the energy transfer shaft when the
first planetary bilobe gear and the second planetary bilobe gear
rotate with planetary revolution about the central axis.
16. The piston system of claim 15 further comprising: a circular
sun gear that is stationary with respect to the stationary
chambers; and the gear stack comprises a circular planetary gear
mounted to revolve around the circular sun gear, the circular
planetary gear being connected to the first planetary bilobe gear
and the second planetary bilobe gear for planetary revolution with
the first planetary bilobe gear and the second planetary bilobe
gear to rotate and revolve with the first planetary bilobe gear and
the second planetary bilobe gear as they revolve around the central
axis.
17. The piston system of claim 16 in which the circular planetary
gear is connected to the first planetary bilobe gear and the second
planetary bilobe gear on a yoke and the yoke rotates with the
energy transfer shaft.
18. The piston system of claim 15, further comprising a balancing
gear stack mounted on a side of the central axis opposite to the
gear stack.
19. The piston system of claim 18, in which the balancing gear
stack comprises: a first balancing planetary bilobe gear meshed to
the first central bilobe gear; a second balancing planetary bilobe
gear meshed to the second central bilobe gear; the first balancing
planetary bilobe gear and the second balancing planetary bilobe
gear being connected to the energy transfer shaft to rotate with
the energy transfer shaft when the first balancing planetary bilobe
gear and the second balancing planetary bilobe gear rotate with
planetary revolution about the central axis; a circular balancing
planetary gear mounted to revolve around the circular sun gear, the
circular balancing planetary gear being connected to the first
balancing planetary bilobe gear and the second balancing planetary
bilobe gear for planetary revolution with the first balancing
planetary bilobe gear and the second balancing planetary bilobe
gear to rotate and revolve with the first balancing planetary
bilobe gear and the second balancing planetary bilobe gear as they
revolve around the central axis; the circular balancing planetary
gear being connected to the first balancing planetary bilobe gear
and the second balancing planetary bilobe gear on the yoke.
20. The piston system of claim 15, in which the gears have double
helical teeth.
21. The piston system of claim 20, in which the first central
bilobe gear and the second central bilobe gear are mounted so that
the long axis of the first central bilobe gear is at 90 degrees to
the long axis of the second central bilobe gear when the first arm
and the second arm are perpendicular to each other.
22-30. (canceled)
31. A piston system, comprising: a piston arrangement coupled to a
first end of an arm for circumferential movement about the central
axis of the arm; the piston arrangement being mounted for
circumferential movement within a fixed chamber that extends
circumferentially about the central axis; the arm being secured to
a shaft that is mounted for rotation about the axis; the shaft
being connected to an energy transfer mechanism; and the energy
transfer mechanism including coupled non-circular gears arranged to
convert oscillatory rotational motion to unidirectional rotational
motion.
32. The piston system of claim 31 in which the piston arrangement
comprises a pair of pistons facing in opposite directions.
33. The piston system of claim 32 further comprising the arm having
a second end extending beyond the central axis in an opposite
direction to the first end, the second end coupled to a second
piston arrangement comprising a pair of pistons facing in opposite
directions.
34. A piston system, comprising: an arm arranged to rotate about an
axis; a piston arrangement coupled to a first end of the arm by a
partial gear pinion section, the piston arrangement including a
piston mounted for movement within a right-cylindrical stationary
chamber; the arm being connected to an energy transfer mechanism;
and the energy transfer mechanism including coupled non-circular
gears arranged to convert oscillatory rotational motion to
unidirectional rotational motion.
35. The piston system of claim 34 in which the piston arrangement
comprises a pair of pistons facing in opposite directions.
36. The piston system of claim 35 further comprising the arm having
a second end extending beyond the axis in an opposite direction to
the first end, the second end coupled to a second piston
arrangement comprising a pair of pistons facing in opposite
directions.
37-39. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 USC 119(e) of
U.S. provisional application Ser. No. 61/666,767 filed Jun. 29,
2012.
TECHNICAL FIELD
[0002] Oscillating piston systems.
BACKGROUND
[0003] Alternatives to the conventional reciprocating engine are
well known (for example, the well-established Wankel engine and
alternatives such as those in U.S. Pat. No. 6,886,527 or
7,600,490). Commonly, parts rotating or oscillating about a central
axis define the working volume of a combustion chamber. Many of
these designs suffer from issues related to seal complexity and
wear, lubrication issues, methods of converting oscillatory motion
or oscillatory rotational motion generated by the combustion
chambers to rotational motion in a shaft, and the challenges
arising from the huge rotational forces that exist in high-speed
rotating systems (see for example U.S. Pat. No. 6,739,307). Well
known methods exist for converting rotational motion with
oscillation to rotational motion, or vice versa (see for example
U.S. Pat. No. 4,844,708), but few satisfactory attempts have been
made at converting net-zero-motion rotational oscillations to
continuous rotation (see for one such example U.S. Pat. No.
5,222,463).
SUMMARY
[0004] In one embodiment, the piston system comprises a first arm
and a second arm, each mounted respectively on a first shaft and a
second shaft, and being mounted coaxially for rotation about a
central axis. Both arms terminate radially outward from the central
axis, coupled to piston arrangements. The piston arrangements
include pistons on either side of each arm. The sets of pistons are
mounted for movement within respective stationary chambers. Each
stationary chamber may be defined, at least in part, by a piston of
the first arm and a piston of the second arm. The piston of the
first arm and the piston of the second arm may be opposed to one
another to capture energy from both ends of the combustion chamber.
The stationary chambers are arranged about the central axis. The
first and the second shaft are connected to an energy transfer
mechanism. The energy transfer mechanism includes coupled
non-circular gears arranged to convert oscillatory rotational
motion to unidirectional rotational motion, for example as
controlled by planetary circular gears referenced to a stationary,
grounded circular sun gear.
[0005] Although conventionally planetary gears often rotate within
an external ring gear, the term "planetary gear" as used in this
document does not require the existence of an external ring gear.
"Oscillatory rotational motion" is used interchangeably with
"rotational oscillatory motion" in this disclosure.
[0006] In one embodiment, the piston arrangements may be toroidal
in shape, travelling in toroidal combustion chambers, and affixed
solidly to the arms.
[0007] In another embodiment, the pistons may be right-cylindrical
in shape, arranged at the two ends of a body of fixed length, and
may be coupled to the arms, preferentially by means of a rack and
partial pinion arrangement, or by other means by which an
oscillating rotational element may be coupled to a linear motion
element.
[0008] In yet another embodiment, the pistons may be
right-cylindrical in shape, with the two pistons in one arrangement
each having an independent mechanism coupling it to the arm,
allowing the two pistons in the arrangement to move equally but at
different angles, preferentially at 90 degrees from each other.
This coupling may be achieved through a partial pinion--to idler
gear--to rack arrangement, or by some other means by which an
oscillating rotational element may be coupled to a linear motion
element at an oblique angle. The pistons from one arrangement may
be collinear with pistons from the other arrangement, resulting in
a fully opposed piston configuration for each stationary
chamber.
[0009] Each stationary chamber may further be defined in part by an
engine block, forming one half of each stationary chamber, and a
head, forming the other half of each stationary chamber. The
combustion chambers may further be partially enclosed within
cylinder sleeves, which may provide seamless chambers within which
the pistons may move. Each stationary chamber may further involve
an intake port and an outtake port, each respective port being
located on a surface of each respective stationary chamber neither
defined nor traversed by a piston. In one embodiment, each intake
port and outtake port is placed on the engine block. Additionally,
the outtake port may lie radially outward, with respect to the
central axis, from the intake port of each respective stationary
chamber. Further, to ensure evenness of burn and venting, each
intake port and exhaust port may be placed equidistant from the
piston of the first arm and the piston of the second arm defining
at least in part each respective stationary chamber. As is usual in
a combustion engine, the intake port may be larger in surface area
than the exhaust port.
[0010] In another embodiment, each intake port and exhaust port
further comprises, respectively, an associated intake valve and an
exhaust valve. The valves may be poppet valves. In addition, the
opening and closing of the intake and exhaust valves may be
controlled by a rotating cam plate. When the piston system is used
as an internal combustion engine, each stationary chamber may
further include an ignition mechanism, which may be possibly a
spark ignition system or compression ignition system as best suits
the fuel of choice for a particular implementation.
[0011] In a further embodiment, the energy transfer mechanism of
the piston system includes an energy transfer shaft, a first
central bilobe gear, and a second central bilobe gear. Both the
first central bilobe gear and the second central bilobe gear may be
mounted for partial rotation about the central axis, on
respectively the first shaft and the second shaft. The energy
transfer mechanism further includes a gear stack. The gear stack
comprises a first planetary bilobe gear meshed with the first
central bilobe gear, and a second planetary bilobe gear meshed with
the second central bilobe gear. Both the first planetary bilobe
gear and the second planetary bilobe gear may be affixed together
and rotationally mounted on a planetary gear shaft connected by
means of a yoke to the energy transfer shaft, to rotate with the
energy transfer shaft as the first and second planetary bilobe
gears rotate with planetary revolution about the central axis,
controlled by a mechanism that maintains a static reference to the
engine block.
[0012] In a further embodiment, the piston system further includes
a circular sun gear stationary with respect to the stationary
chamber. The circular sun gear may be affixed to the engine block,
providing a constant reference and anchor point for both motion and
energy transfer. The gear stack further includes, as a mechanism to
maintain a stabilizing reference to the engine block, a circular
planetary gear mounted to revolve around the circular sun gear. The
circular planetary gear may be fixed to the first planetary bilobe
gear and the second planetary bilobe gear for rotation and
planetary revolution with the first planetary bilobe gear and the
second planetary bilobe gear. The gear stack may be coupled to the
energy transfer shaft in such a way as to link net-zero-motion
oscillation of the central non-circular gears through rotational
and revolutionary motion of the planetary gear stack to rotational
motion of the energy transfer shaft with respect to the stationary
circular sun gear. The circular planetary gear may be fixed to the
first and second planetary bilobe gears and rotationally mounted on
a planetary shaft connected to a yoke coupled to the energy
transfer shaft to rotate with the energy transfer shaft.
[0013] With the circular planetary gear fixed in revolutionary and
rotational motion with the first and second planetary bilobe gears,
the first planetary bilobe gear may control the oscillatory motion
of the first central bilobe gear, which may, in turn, be connected
through the first shaft to the first arm and coupled to a piston
arrangement. Similarly, the second planetary bilobe gear, possibly
being mounted with its major axis perpendicular to that of the
first planetary bilobe gear, may control the oscillatory motion of
the second central bilobe gear, which may, in turn, be connected
through the second shaft to a second arm coupled to a piston
arrangement.
[0014] The first central bilobe gear and the second central bilobe
gear may further be mounted so that their major axes are
perpendicular to each other when the first arm and the second arm
are perpendicular to each other.
[0015] In a further embodiment, a balancing planetary gear stack
may be mounted on a side of the central axis opposite the gear
stack. The balancing gear stack may equalize forces experienced by
moving parts, and may provide a natural balancing mass for the
first planetary gear stack. The balancing gear stack may include a
first and a second balancing planetary bilobe gear meshed
respectively with the first and second central bilobe gears. Both
the first and second balancing planetary bilobe gears may be
rotationally mounted on a planetary gear shaft connected to the
energy transfer shaft through a yoke to rotate with the energy
transfer shaft when the first and second balancing planetary bilobe
gears rotate with planetary revolution about the central axis. The
balancing gear stack may further include a balancing circular
planetary gear mounted to revolve around the circular sun gear,
being affixed to the first and second balancing planetary bilobe
gears and rotationally mounted on a planetary gear shaft connected
to the yoke so as to rotate and revolve with the first and second
balancing planetary bilobe gears.
[0016] In an additional embodiment, the first bilobe planetary
gear, the first central bilobe gear, the second bilobe planetary
gear, and the second central bilobe gear are double helical gears.
Preferably, when double helical gears are used, all the gears in
the energy transfer mechanism are double helical gears. Double
helical gears are used to allow for significantly higher rotational
velocity and energy transfer as compared to spur gears, while
eliminating the need for thrust bearings as would be required for
single helical gears.
[0017] In a further embodiment, the energy transfer mechanism may
function as a self-contained device, without the piston system, to
convert unidirectional rotational motion to net-zero-motion
oscillation, or vice versa. The resulting oscillation may be that
of differential motion between two concentric shafts, or, using
only one set of non-circular gears in conjunction with the
controlling circular gears, may produce oscillatory motion of a
single shaft.
[0018] The energy transfer mechanism may comprise a fixed shaft
defining a central axis, whether physically at the center or as the
outside shaft sleeve of a concentric set of shafts, an energy
transfer shaft, a first bilobe gear mount shaft and a second bilobe
gear mount shaft mounted for net-zero-motion rotational oscillation
about the central axis. Additionally, the energy transfer mechanism
may comprise a first central bilobe gear mounted for
net-zero-motion rotational oscillation about the central axis on
the first bilobe gear mount shaft, a second central bilobe gear
mounted for net-zero-motion rotational oscillation about the
central axis on the second bilobe gear mount shaft, a circular sun
gear that is stationary with respect to the fixed shaft, a gear
stack comprising a first planetary bilobe gear meshed with the
first central bilobe gear, and a second planetary bilobe gear
meshed with the second central bilobe gear. Further, the energy
transfer mechanism may include a circular planetary gear mounted to
revolve around the stationary circular sun gear, the circular
planetary gear being fixed to the first planetary bilobe gear and
the second planetary bilobe gear for planetary revolution with the
first planetary bilobe gear and the second planetary bilobe gear.
The first planetary bilobe gear and the second planetary bilobe
gear may be affixed together and rotationally mounted on a
planetary gear shaft connected to the energy transfer shaft to
rotate with the energy transfer shaft when the first planetary
bilobe gear and the second planetary bilobe gear rotate with
planetary revolution about the central axis.
[0019] In a further embodiment an energy transfer mechanism may
comprise a fixed shaft defining a central axis, an energy transfer
shaft mounted for rotation about the central axis and a bilobe gear
mount shaft mounted for rotational oscillation about the central
axis, a central bilobe gear mounted for rotational oscillation
about the central axis on the bilobe gear mount shaft, a circular
sun gear that is fixed with respect to the fixed shaft, and a gear
stack comprising a planetary bilobe gear meshed with the central
bilobe gear, a circular planetary gear mounted to rotate as it
revolves around the circular sun gear, the circular planetary gear
being connected to the planetary bilobe gear to rotate and revolve
with the planetary bilobe gear as it revolves about the central
axis, the planetary bilobe gear being connected to the energy
transfer shaft to rotate with the energy transfer shaft when the
planetary bilobe gear rotates as it revolves about the central
axis. There may also be a balancing gear stack mounted on a side of
the central axis opposite to the gear stack. The balancing gear
stack may comprise a balancing planetary bilobe gear meshed to the
central bilobe gear, the balancing planetary bilobe gear being
connected to the energy transfer shaft to rotate with the energy
transfer shaft when the balancing planetary bilobe gear rotates as
it revolves about the central axis, and a circular balancing
planetary gear mounted to revolve around the circular sun gear, the
circular balancing planetary gear being connected to the balancing
planetary bilobe gear to rotate as it revolves with the balancing
planetary bilobe gear to rotate and revolve with the balancing
planetary bilobe gear as it revolves about the central axis, the
circular balancing planetary gear being connected to the first
balancing planetary bilobe gear on the yoke.
[0020] In a further embodiment a piston system may comprise a
piston arrangement coupled to a first end of an arm for
circumferential movement about the central axis of the arm, the
piston arrangement being mounted for circumferential movement
within a fixed chamber that extends circumferentially about the
central axis, the arm being secured to a shaft that is mounted for
rotation about the axis, the shaft being connected to an energy
transfer mechanism, the energy transfer mechanism including coupled
non-circular gears arranged to convert oscillatory rotational
motion to unidirectional rotational motion. In a further embodiment
the piston arrangement may comprise a pair of pistons facing in
opposite directions. The arm may have a second end extending beyond
the central axis in an opposite direction to the first end, the
second end coupled to a second piston arrangement comprising a pair
of pistons facing in opposite directions.
[0021] In a further embodiment a piston system comprises an arm
arranged to rotate about an axis, a piston arrangement coupled to a
first end of the arm by a partial gear pinion section, the piston
arrangement including a piston mounted for movement within a
right-cylindrical stationary chamber, the arm being connected to an
energy transfer mechanism, and the energy transfer mechanism
including coupled non-circular gears arranged to convert
oscillatory rotational motion to unidirectional rotational motion.
The piston arrangement may comprise a pair of pistons facing in
opposite directions. The arm may have a second end extending beyond
the axis in an opposite direction to the first end, the second end
coupled to a second piston arrangement comprising a pair of pistons
facing in opposite directions.
[0022] In a further embodiment a piston system comprises an arm
arranged to rotate about an axis, an end of the arm terminating in
a partial gear pinion section coupled to an idler gear further
coupled to a piston arranged to move within a right-cylindrical
stationary chamber, each of the first shaft and the second shaft
being connected to an energy transfer mechanism, and the energy
transfer mechanism including coupled non-circular gears arranged to
convert oscillatory rotational motion to unidirectional rotational
motion. The idler gear may be further connected to a further piston
in a further right cylindrical chamber. The arm may have a second
end extending beyond the axis in an opposite direction to the first
end, the second end terminating in a partial pinion section coupled
to an idler gear connected to a pair of pistons arranged to move in
respective right cylindrical chambers.
[0023] These and other aspects of the device and method are set out
in the claims, which are incorporated here by reference.
BRIEF DESCRIPTION OF THE FIGURES
[0024] Embodiments will now be described with reference to the
figures, in which like reference characters denote like elements,
by way of example, and in which:
[0025] FIG. 1 is a simplified diagram of eight toroidal piston
faces arranged on two piston assemblies.
[0026] FIG. 2 shows the arrangement of the piston faces when the
top and bottom chambers are undergoing compression.
[0027] FIG. 3 shows the arrangement of the piston faces when the
top and bottom chambers are undergoing expansion.
[0028] FIG. 4 is a perspective section of toroidal pistons shown
within their combustion chambers, fixed to the oscillator arms.
[0029] FIG. 5 is a perspective section of pistons of
right-cylindrical shape coupled to the oscillator arms by means of
a partial pinion and rack arrangement.
[0030] FIG. 6 is a perspective section of independent pistons of
right-cylindrical shape arranged so that pistons of one arm are
collinear with pistons of the other arm, coupled to the arms by
means of a partial pinion--to idler gear--to rack arrangement.
[0031] FIG. 7 is a perspective of a stationary chamber in a
toroidal configuration, viewed from above.
[0032] FIG. 8 shows a vertical cross-section view of a toroidal
stationary chamber through one of the pistons.
[0033] FIG. 9 is a perspective of a stationary chamber arranged
between pistons of right-cylindrical shape in an arrangement where
the pistons are typically coupled to the oscillator arms by means
of a rack and partial pinion arrangement.
[0034] FIG. 10 is a perspective of a stationary chamber arranged
between fully-opposed pistons in an arrangement where the pistons
are coupled to the oscillator arms by means of a partial pinion to
idler gear to rack arrangement.
[0035] FIG. 11 is a cut-away view of the intake and exhaust ports
and their corresponding poppet valves.
[0036] FIG. 12 is a vertical view of the valve cam plate associated
with the intake and exhaust poppet valves.
[0037] FIG. 13 is a vertical cross section of the energy transfer
mechanism and the piston assembly.
[0038] FIG. 14 is a transparent view of an energy transfer
mechanism with two gear stacks using double helical gears.
[0039] FIG. 15 is a cross section view of an energy transfer
mechanism through the lower set of non-circular gears.
[0040] FIG. 16 is a cross section view of an energy transfer
mechanism through an upper set of non-circular gears.
[0041] FIG. 17 is a cross section view of an energy transfer
mechanism through the circular gears.
[0042] FIG. 18 is a perspective view of a double helical elliptical
bilobe gear.
[0043] FIG. 19 is a transparent view of an energy transfer
mechanism with a single planetary gear stack employing double
helical gears for high-speed low-power applications.
[0044] FIG. 20 is a transparent view of an energy transfer
mechanism with two gear stacks employing spur-cut gears for
low-speed high-power applications.
[0045] FIG. 21 is a transparent view of an energy transfer
mechanism with spur-cut gears, with a single planetary gear stack,
for low-speed low-power applications.
[0046] FIG. 22 is a transparent view of an energy transfer
mechanism with spur-cut gears, with only a single set of
non-circular gears, for a low-speed high-power single oscillator
application.
[0047] FIG. 23 is a transparent view of an energy transfer
mechanism with a single planetary gear stack with spur cut gears,
with only a single set of non-circular gears, for a low-speed
low-power single oscillator application.
DETAILED DESCRIPTION
[0048] Immaterial modifications may be made to the embodiments
described here without departing from what is covered by the
claims.
[0049] As seen in FIG. 1, the four combustion cycles act between
eight piston faces on two piston assemblies. The first piston
assembly consists, in part, of a first arm 10 mounted on a first
shaft 12, and rotates about a central axis A. Similarly, the second
piston assembly consists, in part, of a second arm 14 mounted on a
second shaft 16 coaxial to the first shaft 12. Both the first and
second arms terminate radially outward from the central axis A in
piston arrangements. Each piston arrangement includes two pistons
18. A piston arrangement may have four piston faces in two pairs of
pistons. The piston assemblies do not rotate, but rather oscillate
back and forth, as shown in FIGS. 2 and 3. Each piston 18
oscillates circumferentially within a corresponding stationary
chamber 20 (FIG. 4). Each stationary chamber 20 is defined in part
by a piston 18 of the first arm 10 and a piston 18 of the second
arm 14. Each stationary chamber extends circumferentially about the
central axis A.
[0050] During one quarter of a complete rotation (FIG. 2) of the
energy transfer mechanism 60 (see below for a detailed
description), compression occurs between two sets of pistons B and
D; and expansion between two other sets of pistons C and E. In the
second quarter of a complete rotation (FIG. 3) of the energy
transfer mechanism, expansion occurs between two sets of pistons B
and D; and compression occurs between the other two sets of pistons
C and E. The process repeats for the third and fourth quarters of a
complete rotation of the energy transfer mechanism 60 producing
four strokes for each chamber per rotation of the energy transfer
mechanism 60, making it the equivalent of a V-8 conventional
engine. Since all forces in the combustion chamber act equally but
in opposite directions on the two piston assemblies, little energy
is distributed to the body of the engine, resulting in increased
efficiency and reduced vibration. Also, since the expansion of the
chamber results from the differential movement of two piston faces,
the actual motion of each piston is only half of the total stroke.
This helps to ensure that rotational forces on key motor components
are kept to a minimum. Wear is minimized, and seals have little
tendency to pull away from their sealing surfaces.
[0051] The pistons may also, for ease of manufacture and further
reduction of rotational forces, be right-cylindrical in shape,
travelling in combustion chambers that are right-cylindrical.
However, to achieve this, the pistons must be separated from the
control arms and linked in a way that converts rotational motion to
linear motion. FIG. 5 shows one such arrangement, in which the two
pistons 102 and 104 at one end of an arm 106 are positioned at each
end of a gear rack 108, coupled to the end of the arm which acts a
partial pinion in a rack and pinion arrangement. This configuration
of the pistons has the advantages of simplicity, ease of
manufacture, and durability; however, the combustion chamber 110
now comprises two sections at right angles to each other, creating
an outward moment acting on the engine block and head during
expansion, thereby losing some of the energy to vibration.
[0052] FIG. 6 shows an arrangement in which the pistons are, again,
right-cylindrical. However, in this arrangement, the two pistons
120 and 122 in a given combustion chamber 130 are fully opposed to
each other, so no energy is lost to the engine block and head. In
order to achieve the necessary motion, the end of an arm 134 is
coupled to an idler 136 which, in turn, is coupled to two pistons
120 and 124, one in each of two combustion chambers 130 and 132.
This configuration has the advantages of full-opposition of the
pistons and ease of manufacture; however, the design is
significantly more complex with a greater parts count.
[0053] All three of the configurations share basic operational
characteristics and design elements; consequently, the remaining
discussion returns to the first configuration, and can be applied
to the other configurations as well. The combustion chambers, being
stationary, are constructed around the pistons 18 by fastening a
head 30 and a matching engine block 32 together. This forms a
fully-enclosed space within which the pistons oscillate, as seen
from above in FIG. 7, and in vertical cross-section in FIG. 8. This
makes possible the use of conventional ring compression seals 21
and lubricant-distribution rings 22, such as those used in the
conventional reciprocating engine--a well-developed and reliable
technology. The combustion chamber may be enclosed by cylinder
sleeves 23, which may provide a seamless chamber within which the
pistons may move.
[0054] Each chamber has an intake port 24 and an exhaust port 26.
The intake port 24 and exhaust port 26 are located on a surface of
the chamber not defined by a piston 18. In particular, the intake
port 24 and exhaust port 26 may be located on the engine block 32.
The ports may be placed at the centre of the chamber, equidistant
from the pistons 18, enhancing the evenness of burn and venting.
Each intake port 24 lies inward from each respective exhaust port
26. FIG. 9 shows the arrangement of the chamber, the intake port,
and exhaust port for the configuration of FIG. 5, and FIG. 10 shows
the same for the configuration of FIG. 6. As shown in FIG. 11, an
intake manifold 40 is on the inside, and exhaust is vented through
the side of the combustion chamber in an exhaust manifold 42. Each
intake port 24 has an associated intake valve 44; each exhaust port
26 has an associated exhaust valve 46. Rather than using intake and
exhaust ports opened and closed by moving pistons, as is typical
for most rotary engines, conventional poppet valves, 44 and 46, are
employed, again using well-developed and reliable technology, as
shown in FIGS. 11 and 12. The valves reside in what would
traditionally be considered the engine block 32, so that they can
be controlled by a rotating cam plate 48. This plate 48 rotates
once per cycle, so, unlike the conventional reciprocating engine,
no additional gearing is required for valve control. The plate
further comprises an intake valve cam track 50 and an exhaust valve
cam track 52 which control the opening and closing of intake valves
44 and exhaust valves 46 as the cam plate rotates.
[0055] Each stationary chamber further comprises a respective
ignition mechanism. Since each combustion chamber fires once per
revolution, ignition timing involves sequential spark generation at
each quadrant of the rotation of the output shaft for the
combustion chamber at each of those quadrants. This spark
generation could involve a simple magneto and points, a
coil/point/condenser ignition system, or an electronic ignition
system. A diesel adaptation of this engine could employ standard
compression ignition techniques.
[0056] The opposing pistons 18 undergo two expansion-compression
oscillations each per rotation of the energy transfer mechanism 60,
exhibiting, in each of the four combustion chambers 20, the four
necessary strokes: intake, compression, combustion, and
exhaust.
[0057] Swing-piston engines often fall prey to the same
disadvantages. Most rotational systems involve parts rotating with
high angular velocity around a central shaft. The centripetal
forces involved in holding these systems together are significant.
Any seals, valves, or other components on the rotating parts are
exposed to uneven and often extreme wear. The use of pressurized
lubrication is limited because most of these systems rely on moving
pistons, vanes, or rotors acting across intake and output ports.
Thus, unlike in traditional reciprocating piston systems,
complicated seals are necessary. This creates significant points of
failure from the types of pitting and corrosion occurring between
the moving components and the ports in the stators. Many rotational
systems involve numerous high-pressure seals between rotating parts
and stators, often complicated by discontinuities between radial
and axial flat or curvilinear surfaces. In addition, motion control
in rotational systems is often complex and bulky, negating the
advantages of the compact rotary system.
[0058] Further, in the oscillatory swing-piston engine, a system is
required to convert the oscillations to rotary motion. Typically,
these systems involve cranks, pins, cams, and connecting rods,
which usually convert rotational motion to linear motion and back
to rotational motion. Although inexpensive, these systems are
relatively complex, and leave room for mechanical failure and loss
of accuracy in motion.
[0059] The present piston system relies on the net-zero-motion
oscillation of pistons. Here, since the piston assemblies each move
only half of the required distance for full displacement,
oscillatory motion is minimal. This avoids the issue of extreme
angular momentum mentioned above. Further, the chambers within
which the pistons move are stationary, and completely surround the
circular face of the pistons, unlike the majority of swing piston
designs, and particularly unlike the design of U.S. Pat. No.
5,222,463, in which the entire block and head of the motor rotate
around the piston arrangement. Thus, in the present design, common
pressure seals and pressurized lubrication may be employed, as in
the conventional reciprocating piston system.
[0060] An energy transfer mechanism 60 converts oscillatory
rotational motion to unidirectional rotational motion (as seen in
FIGS. 13 and 14). The energy transfer mechanism is connected to the
first piston arm 10 and the second piston arm 14 through,
respectively, the first shaft 12 and the second shaft 16. The
energy transfer mechanism includes coupled non-circular gears.
These are arranged to convert the oscillatory rotational motion of
the piston arms and their corresponding shafts to unidirectional
rotational motion in an energy transfer shaft 62.
[0061] The energy transfer mechanism 60 is constructed as follows.
The basic design is illustrated in FIGS. 13 and 14. For the sake of
clarity, the discussion will be based on the use of elliptical
bilobe gears (ie bilobe gears derived from unilobe ellipses) as the
preferred non-circular gear configuration. Other configurations,
such as elliptical unilobe, trilobe, square, or custom-designed
gears could also be used, resulting in compression-expansion
patterns other than the four strokes required for the present
internal combustion engine. However, each configuration would
require specific engineering to ensure constant shaft center
distance and pressure angle.
[0062] A first central bilobe gear 70 (FIG. 15) is mounted for
oscillatory rotational motion about the central axis A on the first
shaft 12. Similarly, a second central bilobe gear 72 (FIG. 16) is
mounted for oscillatory rotational motion about the central axis A
on the second shaft 16. A first planetary bilobe gear 74 (FIG. 15)
is meshed with the first central bilobe gear 70; a second planetary
bilobe gear 76 (FIG. 16) is meshed with the second central bilobe
gear 72. The first and second planetary bilobe gears are arranged
into a planetary gear stack 78. The planetary gear stack 78 is
rotationally mounted on a planetary gear shaft connected to the
energy transfer shaft 62 to rotate with planetary revolution about
the central axis A, and revolves with the energy transfer shaft 62.
The first set of bilobe gears corresponds to the oscillation of the
first piston assembly; the second set of bilobe gears corresponds
to the second piston assembly. The first central bilobe gear 70 and
the second central bilobe gear 72 are mounted so that they are 90
degrees to each other when the first arm and the second arm are
perpendicular to each other.
[0063] A circular sun gear 80 (FIG. 17) is included, the sun gear
being stationary with respect to the stationary chambers 20. It is
possible to provide a fixed reference to the circular sun gear
either by means of an outside concentric fixed shaft 19, as shown
in FIGS. 13,14 and 19, or by a central fixed shaft, as shown in
FIGS. 15-17 and 20-23. The choice of reference affects the order in
which the layers of gears appear. The central, stationary, circular
sun gear 80 maintains alignment of all the moving parts. The gear
stack 78 further comprises a circular planetary gear 82, meshed
with the circular sun gear 80. The circular planetary gear 82
revolves around the circular sun gear 80, being fixed to the first
planetary bilobe gear 74 and the second planetary bilobe gear 76
for planetary revolution with the first planetary bilobe gear 74
and the second planetary bilobe gear 76. The circular planetary
gear 82 is fixed to the first planetary bilobe gear 74 and the
second planetary bilobe gear 76 and rotationally mounted on a
planetary gear shaft connected to a yoke 84. The yoke 84 rotates
with the energy transfer shaft 62. The axis of the yoke 84 is
coaxial to the central axis A. Since the planetary non-circular
gears are affixed to the circular planetary gears, they make a
single rotation in half a revolution of the yoke.
[0064] In a preferred embodiment, the balancing gear stack 86 is
diametrically opposed to the first gear stack 78. The balancing
gear stack may handle an equal amount of power to the first gear
stack, and may equalize forces within the energy transfer
mechanism. The balancing gear stack 86 is similar in construction
to the first gear stack 78. A first balancing planetary bilobe gear
87 (FIG. 15) is meshed to the first central bilobe gear 70; a
second balancing planetary bilobe gear 88 (FIG. 16) is meshed to
the second central bilobe gear 72. A circular balancing planetary
gear 90 (FIG. 17) is mounted to revolve around the circular sun
gear 80. The balancing gears are affixed together and rotationally
mounted on a planetary gear shaft connected to the energy transfer
shaft to rotate with the energy transfer shaft when the balancing
planetary gears rotate with planetary motion about the central axis
A. The circular balancing planetary gear 90 is fixed to the first
balancing planetary bilobe gear 86 and the second balancing
planetary bilobe gear 88 and together they are rotationally mounted
on a planetary gear shaft through the yoke 84. The balancing gear
stack moves with planetary revolution about the central axis A.
[0065] As the gear stack 78 revolves around the stationary sun gear
80, the central bilobe gears must oscillate back and forth due to
the variation of the instantaneous radii of driven and driving
gears, as in the explanation that follows. The two oscillate in
opposite rotational direction to each other, since the non-circular
planetary gears are at 90 degrees to each other.
[0066] When the instantaneous radius of a planetary gear is greater
than that of a corresponding central gear, the central gear moves
in opposite rotational direction from the energy transfer shaft 62
and the yoke 84. When the instantaneous radius of a planetary gear
is less than that of a corresponding central gear, the central gear
moves in the same rotational direction as the transfer shaft 62 and
the yoke 84. However, since the total perimeter of the central and
planetary gears is identical, the net rotational motion of the
central gear for a half revolution of the planetary assembly is
zero. If the non-circular gears are bilobe gears, the central
bilobe gear, and the oscillator shaft attached thereto, complete
two complete oscillations per rotation of the case and energy
transfer shaft 62, motion suited to a four-stroke internal
combustion engine. The above explanation in this paragraph assumes
that the planetary gears have the same total perimeter as the
central gears and that the lobed planetary gears have the same
number of lobes as the lobed central gears. Alternatively, the
planetary gears may have a different perimeter from the central
gears and a corresponding different number of lobes. In this case,
when the ratio of the instantaneous radius of a planetary gear to
the instantaneous radius of a corresponding non-circular central
gear is greater than the ratio of the radius of the circular
planetary gear to the radius of the circular sun gear, the
non-circular central gear moves in an opposite rotational direction
from the energy transfer shaft 62 and the yoke 84. When the former
ratio is smaller than the latter ratio, the non-circular central
gear moves in the same rotational direction as the transfer shaft
62 and the yoke 84.
[0067] For high-speed operation, helical gears are preferred, best
configured as double helical gears 92 to eliminate thrust, as in
FIG. 18. A helical gear can operate at approximately five times the
speed of a spur-cut involute gear. Single-helix gears experience a
great deal of end thrust due to the angle of contact of the teeth.
Typically, this is addressed by placing thrust bearings on the
sides to which the gears are forced by the helices. However, in an
oscillator, this force will be at one instant towards one side, and
in the next instant towards the other side. Rather than designing
for thrust bearings on both sides of all gears, double helical
gears may be utilized, as these exhibit no end thrust other than
for basic positioning, and are self-aligning, as seen in FIG. 18.
Manufacturing double helical teeth on non-circular gears, at first
glance, appears to be a very complex and daunting challenge.
Although the mathematical relationships are quite complex, they are
based on a relatively simple mechanical concept--that of using a
single straight-edged "rack tooth" cutter with the appropriate
pressure angle to cut each tooth, as the gear, held at the angle of
the helix, rotates with the gear axis moving laterally to match the
instantaneous radius. Each tooth automatically changes shape from
top to bottom, and each tooth is unique as a result of this cutting
process, as required for proper operation. In a typical
manufacturing process, this same cut can be achieved by using a
gear shaper in which a circular plunge cutter is made to rotate by
the angle necessary to produce the desired helix during each
plunge, and, as the cutter and gear blank advance for the next
plunge, the centre distance and rotation angle of the gear blank
are adjusted to produce the required pressure angle and
instantaneous radius.
[0068] Properly designed gears are engineered for strength and
longevity, based upon the power transferred, the meshing velocity
of the teeth, the pressure angle, the service factor (in turn based
on the level of shock experienced by the teeth), a strength factor
based on the type of material and number of teeth, and whether the
teeth are subjected to repetitively reversing loading forces. With
all of these factors taken into account, it becomes a matter of
maximizing the strength of the gears while minimizing the size and
complexity of the design. With double helical teeth, there are
various additional design characteristics to be considered.
Circular pitch, helix angle, and gear face depth affect the number
of teeth that mesh at any given time, which in turn affects the
required strength of the teeth. Since the gears in the current
design rotate on a one-to-one basis, the same teeth mesh together
for each revolution, and the loading at each meshing point is
always in the same direction--some points are always driven, others
are always driving. This means that the calculation for gear
longevity results in a much longer life expectancy than for a gear
on which the teeth experience reversible loading.
[0069] All of this analysis and the associated calculations
indicate that bilobe gears with characteristics suitable for high
power and high speed may be engineered to perform with precision,
high reliability, and long life expectancy.
[0070] There are a number of possible design variations. Different
non-circular gear configurations could be employed. The elliptical
bilobe gears produce a variation in motion that very closely
approximates the sinusoidal expansion and compression of the
conventional internal combustion engine; however, the shape of the
control gears could be changed to maximize efficiency by more
closely matching the curves of the Carnot Cycle or by determining a
yet more efficient relationship between compression and the
expansion resulting from the combustion of gases. Since the valve
cam plate system is simple, it could be adapted to allow for
infinitely variable valve control, both in terms of timing and
throw. For small engine applications, the poppet valves could be
replaced with a rotary valve system, in which gaps in rotating
cylindrical sections mounted on what was shown previously as the
cam plate would provide access to the intake and exhaust ports.
[0071] There are several possible other applications. As with any
piston system, this piston system could also be used as a fluid
pump. As such, more than one set of pistons could be controlled by
the same planetary gearing arrangement. For example, in an internal
combustion engine, other concentric sets of pistons could be placed
on the existing piston assemblies to pump lubricant or fuel.
Depending on the nature of the fluid being pumped, the valves could
be replaced with ports controlled by the moving pistons.
Alternatively, additional cam tracks could be added to the cam
plate to drive piston pumps for lubricant or fuel. This system
adapts well to operation using external pressure sources, such as
compressed air or steam. These applications are two-stroke, an
arrangement which may be accommodated by putting a second set of
cams on the valve cam plate. The two-stroke arrangement could also
be used for a two-stroke internal combustion engine. Using trilobe
non-circular gears, a six-stroke system could be employed, such as
an internal combustion/steam hybrid. An electrical generator or
alternator could be built into the energy transfer mechanism to
make the engine into an internal combustion/electric hybrid. By
changing the phase relationship of the bilobe gears and introducing
a fixed divider at the centre of each chamber, the Sterling Cycle
could also be accommodated.
[0072] The non-circular planetary gear arrangement, in itself,
could be used as a mechanical oscillator for a number of
non-engine-related applications. Devices that could employ a
dependable rotational mechanical oscillator could include
industrial shears and presses, clothes washing machines, mixers,
and kitchen tools. In the development of this design, software to
produce involute curves on non-circular gears was developed,
including the stacking of multiple layers of profiles suitable for
characterizing the faces of double helical non-circular gears. This
software and the mathematical relationships developed to make it
possible could be used in the production of such gears for
applications other than the current design.
[0073] The energy transfer mechanism can be modified for various
other applications. For example, the basic oscillator design can be
modified for low power applications, low speed applications, and
lower cost. In addition, one set of gears can be left out if a
single oscillator is desired. FIG. 19 shows a high-speed lower
power application 100, with one gear stack left out. This would
require counterbalancing, which is not shown in the figure.
[0074] For low speed and relatively high power, the double helical
gears can be replaced with spur-cut gears 102, as shown in FIG. 20.
FIG. 20 also shows a different configuration in which the circular
sun gear is held stationary by a central shaft rather than an
external sleeve, placing it at the bottom of the gear stack instead
of the top.
[0075] For low-speed, low-power applications 104, one of the gear
stacks can again be removed, as shown in FIG. 21. This would
require counterbalancing, which is not shown in the figure.
[0076] If only a single oscillating element is required 106, one of
the layers of non-circular gears can be removed, with the
corresponding shaft, as shown in FIG. 22. One of the gear stacks
could be removed if the single oscillator is not required to handle
high power 108, as in FIG. 23. Again, counterbalancing would be
needed.
[0077] Another configuration would involve three layers of
non-circular gears, with their long axes offset by 60.degree.
instead of 90.degree. to produce 3-phase oscillation on three
concentric oscillating shafts.
[0078] In addition, custom oscillatory motion can be produced by
designing non-circular gears that produce other patterns of motion.
Different non-circular gear configurations are possible: for
example, the base design involves bilobe gears for two complete
oscillations (four strokes) per revolution; unilobe gears would
provide one oscillation (two strokes) per revolution; trilobe gears
would provide three oscillations (six strokes) per revolution;
square gears would provide four oscillations (eight strokes) per
revolution; custom gear profiles could provide specialized
oscillator motion. The primary limitations on design would be
maintaining a constant centre distance and ensuring that the teeth
do not disengage at any point in the rotation. In addition,
discontinuous motion should be avoided where possible to prevent
excessive forces on the gears and subsequent wear.
[0079] Non-circular gears are gears having a pitch shape that is
not circular. In order for two Non-Circular gears to mate properly,
their pitch shapes must roll on each other without slip. This means
that the sum of their instantaneous pitch radii must equal the
centre distance at all times, and that the arcs between matching
points on the pitch shapes must also be equal. Non-circular gears
that may be used include any non-circular bilobe gear set in which
the sums of the instantaneous radii equal the center distance with
pitch shapes which roll on each other without slipping. Elliptical
bilobes produce a very-nearly sinusoidal result; another
combination may produce a "first and third harmonic" shape,
etc.
[0080] A unilobe gear has one section in which the instantaneous
radii at given points are greater than the average radius and one
section in which the instantaneous radii at given points are less
than the average radius. Unilobe gears generate a single complete
cycle of speed change per rotation.
[0081] An elliptical gear is defined by a set of points in a plane,
such that the sum of the distances from two fixed points--the
foci--to any point in the set is a constant. This enables
elliptical gears cut about their foci to run at a constant center
distance. Elliptical gears are often used where unilobe gears are
required.
[0082] A bilobe gear is a gear that has two sections in which the
instantaneous radii at given points are greater than the average
radius and two sections in which the instantaneous radii at given
points are less than the average radius. Bilobe gears generate two
complete cycles of speed variation per rotation.
[0083] Elliptical bilobe gears are gears generated by plotting, in
polar form, each instantaneous radius from one focus of the
generating ellipse but at half of the angle for that instantaneous
radius observed in the generating ellipse. Since the 360.degree. of
the generating ellipse have been compressed into 180.degree., the
instantaneous radius at 0.degree. is equal to the instantaneous
radius at 180.degree., placing the generating focus at the center
of the bilobe gear. The lower side of the bilobe shape is a
duplicate of the upper side.
[0084] In the claims, the word "comprising" is used in its
inclusive sense and does not exclude other elements being present.
The indefinite articles "a" and "an" before a claim feature do not
exclude more than one of the features being present. Each one of
the individual features described here may be used in one or more
embodiments and is not, by virtue only of being described here, to
be construed as essential to all embodiments as defined by the
claims.
* * * * *